Heretofore known is the crayon essentially composed of a colorant, an organic solvent, a resin component and a gelation agent. For example, the crayon produced by using a resin component and at least one gelation agent selected from the group consisting of dibenzylidene-sorbitol and tribenzylidene-sorbitol, inclusive of their derivatives, is known (Japanese Examined Patent Publication S54-23619). This crayon is characterized in that it is not only resistant to degradation even at high temperature and adheres well to the surfaces of various materials (metals, plastics, etc.) but gives a film on writing which becomes hard enough to prevent migration of the color.
Meanwhile, the crayon representing further improvements in hardness, adhesion, writing properties, etc. is also known (Japanese Examined Patent Publication S55-41716). Thus, there is known a crayon comprising (a) at least one member selected from the group consisting of cellulosic resin and vinyl resin, (b) at least one member selected from the group consisting of ketone resin, xylene resin, amide resin and terpene resin, (c) at least one member selected from the group consisting of dibenzylidene-sorbitol and tribenzylidene-sorbitol, inclusive of their derivatives, (d) at least one member selected from the group consisting of glycols, glycol ethers, glycol ether esters and benzoic acid esters, and (e) a colorant.
Aside from the above, there also is known a solid writing material comprising a gelation agent, an organic solvent, a resin component and a colorant characterized in that, as the gelation agent, a benzylidene-sorbitol is used and, as the organic solvent, at least two kinds of solvents, namely a main solvent comprising an aliphatic lower alcohol and an auxiliary solvent comprising an aprotic polar solvent, are used in combination (Japanese Unexamined Patent Publication H8-120209).
However, even these solid compositions call for improvements in writing properties in order that they may be applied to varied materials with satisfactory results. Particularly, any solid composition allowing writing on a wet surface, if developed, should contribute to an expanded crayon market but the crayons so far available can hardly be used successfully on a wet surface.
Meanwhile, the safety regulations are getting more and more stringent of late in various countries of the world and the development of solid compositions clearing the safety bar with a sufficient margin is being demanded. Particularly in respect of the solvent for use in such a solid composition, there is needed for improvement in safety. In this connection, if only for enhancement in safety, the use of an alcohol (especially ethanol) as the solvent may be contemplated. However, when an alcohol is used as the solvent, acceptable writing properties and adhesion cannot be obtained.